题意:已知,可得出 P(1) = 4, P(2) = 1, P(3) = 5,由此可得出 P(P(1)) = P(4) = 2. And P(P(3)) = P(5) = 3,因此.经过k次如上变换,最终可得,输入保证一定有解,求k. 分析: 1.能用数组表示映射就别用map,很耗时 2.序列中的每个数字经过这种变换都一定会变会自身,例如,一开始P(1) = 4,接下来P(P(1)) = P(4) = 2,再接下来P(P(P(1))) = P(P(4)) = P(2) = 1,只需三次,就可以变…

The cube, 41063625 (3453), can be permuted to produce two other cubes: 56623104 (3843) and 66430125 (4053). In fact, 41063625 is the smallest cube which has exactly three permutations of its digits which are also cube. Find the smallest cube for whic…

国外的文献汇总: <Network Traffic Classification via Neural Networks>使用的是全连接网络,传统机器学习特征工程的技术.top10特征如下: List of Attributes Port number server Minimum segment size client→server First quartile of number of control bytes in each packet client→server Maximum n…

题意: 给出n个元素,请产生出所有的全排列. 思路: 注意到可能会有相同的排列出现,比如 {2,2}.还有可能是乱序列(大部分情况下都是无所谓的). 递归(1):产生的过多的多余vector. class Solution { public: void recursion(vector<int> num, int i, vector<vector<int> > &res) { ==num.size()) res.push_back(num); else { fo…

Problem UVA11925-Generating Permutations Accept: 214  Submit: 1429Time Limit: 1000 mSec Problem Description A permutation on the integers from 1 to n is, simply put, a particular rearrangement of these integers. Your task is to generate a given permu…

辗转相除法(又称欧几里得算法)是求最大公因数的算法 要求a,b的最大公约数(a>b),我们可以递归地求b,a%b的最大公约数,直到其中一个数变成0,这时另一个数就是a,b的最大公约数. C++实现: int gcd(int a,int b){ retuen b?gcd(b,a%b):a; } 或: while(b!=0)  {  temp=a%b;   a=b;   b=temp; } 证明:(引自百度百科) 设两数为a.b(b<a),用gcd(a,b)表示a,b的最大公约数,r=a (mod…

CodeForces - 1154G You are given an array a consisting of n integers a1,a2,…,an . Your problem is to find such pair of indices i,j (1≤i<j≤n) that lcm(ai,aj) is minimum possible. lcm(x,y) is the least common multiple of x and y (minimum positive numbe…

The “U.S. Robots” HQ has just received a rather alarming anonymous letter. It states that the agent from the competing «Robots Unlimited» has infiltrated into “U.S. Robotics”. «U.S. Robots» security service would have already started an undercover op…

点我看题目 题意  : 这个人在左下角,地铁在右上角,由很多格子组成的地图,每一条边都是一条路,每一条边都是100米.还有的可以走对角线,问你从起点到终点最短是多少. 思路 : 其实我想说一下,,,,,这个题基本都是用DP做的,这是为什么呢?好吧,这要从我最近要刷BFS题开始,于是二货自己很厉害的用BFS做完了,所以就给我推荐了,我其实没看出来能用BFS来做....... //URAL 1119 #include <iostream> #include <stdio.h> #inc…

1. 原题链接 https://leetcode.com/problems/permutations/description/ 2. 题目要求 给定一个整型数组nums,数组中的数字互不相同,返回该数组所有的排列组合 3. 解题思路 采用递归的方法,使用一个tempList用来暂存可能的排列. 4. 代码实现 import java.util.ArrayList; import java.util.List; public class Permutations46 { public static…